Apparatus for driving a movable tape



Jul 1, 1969 s. JURA APPARATUS FOR DRIVING A MOVABLE TAPE Filed Dec. 2. 1966 Sheet 0 2 X E E 7 *1 r 0- 1/8 "5/ Q, 5?

INVENTOR.

July 1, 1969 s. JURA 3,452,909

APPARATUS FOR DRIVING A MOVABLE TAPE Filed Dec. 2. 1966 Sheet 3 of 2 INVENTOR.

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United States Patent U.S. Cl. 226-50 Claims ABSTRACT on THE DISCLOSURE A movable tape is threaded through a narrow longitudinal aperture disposed in a nozzle. Within the nozzle a pair of converging streams of air impinge obliquely on the opposite surfaces of the tape threaded therethrough to propel the tape forward at a speed determined by the degree of obliqueness and the velocity of the air streams.

Background of invention Existing methods of starting, propelling and braking movable tapes such as magnetic and punched paper tapes commonly employ systems of rollers, capstans and brakes that physically engage the tape. Such arrangements suffer from two basic disadvantages: (1) They are not adaptable for high tape speeds, e.g., speeds of 70 feet per second and more; and (2) the constant physical contact between the tape and at least a portion of such drive systems may cause severe damage to the tape.

Summary of invention In order to obviate these disadvantages, an arrangement has been devised to drive the tape by directing streams of gas of selectable velocity to impinge on opposite surfaces of the tape so that a portion of the kinetic energy of the gas streams is transferred ot the tape. No physical contact exists between the tape and the gas conveyor (i.e., the tape drive), and the speed imparted to the tape by the gas streams is theoretically limited only only by the velocity of the gas streams and the angle at which the gas streams impinge on the tape.

In particular, the gas conveyor may include an elongated nozzle having a narrow longitudinal slot through which the tape to be driven may be freely threaded. The nozzle is provided with a pair of tapered channels symmetrically disposed with respect to the plane of the slot and forming acute angles therewith. The narrower end of each channel communicates with the slot, and the gas streams are respectively coupled into the wider ends of both channels from a common inlet.

If operation of the tape in a single direction only is desired, the tape is threaded through a single nozzle which is oriented in the forward direction of the tape. If bi-directional operation is desired, the tape is threaded through oppositely directed, individually controlled nozzles which are longitudinally spaced. In the latter case, assistance in braking and in holding the tape in a stationary position may be provided by additionally incorporating an intermediate nozzle that is transversely spaced from the tape and so oriented that the stream of gas therefrom impinges perpendicularly on the tape.

Brief description of the drawing The nature of the present invention and its various advantages and features will appear more fully from the following detailed description when taken in connection with the appended drawing, in which:

FIG. 1 is a front view, partly in section, of a nozzle constructed in accordance with the instant invention;

3,452,909 Patented July 1, 1969 FIG. 2 is a plan view, in section, of the nozzle of FIG. 1;

FIG. 3 is a side view, partly in section, of the nozzle of FIGS. 1 and 2 FIG. 4 is a view, partly in section, of a valve arrangement suitable for regulating the flow of gas to the nozzles of FIGS. 1-3;

FIG. 5 is a pictorial diagram of a bi-directional tape driving system employing the nozzles of FIGS. 1-3; and

FIG. 6 is a pictorial diagram of an overall recording unit employing the arrangements of FIGS. 13 and 5.

Detailed description Referring now to FIGS. 1-3 of the drawing, an illustrative embodiment of the invention in the form of an elongated air nozzle is depicted. A movable tape 1 to be driven is threaded through a longitudinal slot (FIG. 3) in the nozzle for the purpose of being exposed to air streams introduced therein. A pair of tapered air channels 7 and 8, both of which are arranged in the approximate shape of a Lavals mouthpiece (FIG. 1), converge upon the longitudinal slot at acute angles to the plane of the tape 1. The channels 7 and 8 open up into the longitudinal slot at a location corresponding to the plane of their narrowest cross-section. The channels 7 and 8 are symmetrically disposed on opposite sides of the tape 1. Thus, no significant component of air flow can exist perpendicular to the axis of the tape. This facilitates centralizing the tape 1 with respect to the upper and lower sides of the slot.

The ends of channels 7 and 8 remote from the longitudinal slot are coupled to an inlet 2 of the nozzle through individual passages defined by upper and lower sets of adjacent ribs 6-6 (FIG. 2). As shown, the number of ribs in each set 6 are sufficient to cover substantially the entire width of the tape 1 to assure a uniform flow of air along the surface of the tape.

The inlet tube 2 couples an air stream from an external source (not shown) to both sets of ribs 66 through a bifurcated region 3 (FIG. 3).

With the scheme shown in FIGS. 1-3, the tape 1 may be driven at high speeds. without danger of damage due to frictional contact between the tape and the nozzle. The tape speed is controlled by regulating the velocity of the air streams introduced into opposite sides of the longitudinal slot through the channels 7 and 8, and thus by regulating the air velocity at the inlet tube 2.

One illustrative method of controlling this air velocity is with the two-position slide valve arrangement shown in FIG. 4. The valve 9' is connected to armatures 10 and 11 of a pair of selectively excited U-shaped electromagnets 12 and 13. By exciting one or the other of the electromagnets 12 or 13, the valve 9 is placed in either the right-hand or left-hand position as shown in FIG. 4, and thus regulates the passage of air into the nozzle from sources (not shown) controlled by the valve.

It will be understood by those skilled in the art that the required air flow regulation may be accomplished manually or, alternatively, with the aid of powered devices such as a closed-loop electropneumatic regulating system.

The nozzle shown in FIGS. 1-3 is uni-directional, i.e., the elfective tape-driving force supplied by the nozzle is only effective in the direction defined by the resultant axial component of air flow from channels 7 and 8 to the longitudinal slot. This direction is to the left as viewed in FIG. 1.

In order to employ such nozzles in a bi-directional tape driving system, the arrangement shown in FIG. 5 may be used. In this case, the tape 1 is threaded through a pair of oppositely directed nozzles 16 and 17. Each of the nozzles 16 and 17 is constructed as shown in FIGS.

1-3 for controlling tape travel to the left and the right, respectively, as viewed in FIG. 5. The air supply for the scheme of FIG. 5 is obtained from a source 20, and is selectively applied to the nozzles 16 and 17 by means of conventional control elements 21 and 23. As an aid in braking and, more importantly, in maintaining the tape 1 in a position of rest opposite an intermediate evaluating circuit 9', an additional nozzle 18 may be provided. The nozzle 18 may be identical to the nozzles 16 and 17 except that the tape is not threaded through the former. Instead, the nozzle 18 is transversely spaced from the tape 1 and is oriented to direct its resultant air flow perpendicularly to the surface of the tape. The air supply for the nozzle 18 is obtained from the common source 20 through a control element 22 identical to the elements 21 and 23.

FIG. 6 shows a magnetic tape recorder unit in which the above-mentioned nozzles are employed as tensioning devices. The tape 1 is wound on a pair of reels 24 and 25. One end of the tape on reel 24 is threaded through a first nozzle 26 to the interior of a first buffer reservoir 28.

Similarly, one end of the tape on the reel 25 is threaded through a nozzle 27 to the interior of a second buffer reservoir 29. The nozzles 26 and 27 are oriented so that their respective air streams are directed into the interior of the associated reservoirs. This serves to compress the tape in the reservoirs and therefore increases the capacity of the latter.

The main drive for the tape 1 is provided by a bidirectional system of nozzles 30 and 31 respectively engaging the ends of the tape 1 at the outputs of the reservoirs 28 and 29. Also, an intermediate braking or holding nozzle 32 is disposed between the nozzles 30 and 31 opposite a bridge 33. The nozzles 30, 31 and 32 may be identical to the nozzles 16, 17 and 18 of FIG. 5. The recorder of FIG. 6 is also provided with a conventional pair of reading and recording heads 34 and 35. Obviously, the operation of the nozzles of FIG. 6 is analogous to that described above in connection with FIGS. 1-3 and 5.

In the foregoing, the invention has been described in connection with preferred arrangements thereof. However, many other modifications will now become obvious to those skilled in the art. Accordingly, it is desired that the breadth of the claims not be limited to the specific disclosure herein contained.

What is claimed is:

1. In a system for positively driving an elongated tape along a longitudinal path, the improvement which comprises:

non-contacting conveying means for directing streams of gas to impinge on opposite surfaces of the tape at an angle with respect thereto,

said conveying means comprises an elongated nozzle provided with first means defining a longitudinal slot for selectively receiving the tape therethrough and second means defining a pair of tapered channels symmetrically and obliquely disposed with respect to the plane of the slot, the narrower ends of the channels communicating with the slot; and the nozzle further includes means for coupling the wider ends of each of the channels to a common inlet means.

2. A system as defined in claim 1, further comprising means for introducing a stream of gas into the inlet means at a selectable velocity.

3. In a system for positively driving an elongated tape along a longitudinal path, in combination, a pair of longitudinally spaced, oppositely directed nozzles each constructed in accordance with claim 1, and means for passing the tape through the slots of the respective nozzles.

4. The combination as defined in claim 3, further comprising an additional nozzle intermediate the oppositely directed nozzles, the additional nozzle being transversely spaced from the tape and positioned to direct the stream of gas to impinge on the tape in a direction perpendicular to the longitudinal axis of the tape.

5. In a recording unit including a pair of tape reels upon which a movable tape may be wound and a pair of tape reservoirs individually associated with the reels, the improvement which comprises, in combination:

non-contacting conveying means for directing streams of gas to impinge 'on opposite surfaces of the tape at an angle with respect thereto;

said conveying means comprising a pair of nozzles each of which is provided with first means defining a longitudinal slot for selectively receiving the tape therethrough and second means defining a pair of tapered channels symmetrically and obliquely disposed with respect to the plane of the slot, the narrower ends of the channels communicating with the slot; and the nozzle further includes means for coupling the wider ends of each of the channels to a common inlet tube;

means for passing the tape through the slots of the respective nozzles; and

means for individually orienting the nozzles to direct the associated streams of gas toward the interior of the respective reservoirs.

References Cited UNITED STATES PATENTS ALLEN N. KNOWLES, Primary Examiner.

U.S. Cl. X.R. 22697, 108 

